The use of UV radiation to kill microorganisms in air or in fluid systems is well known. Often such systems comprise UV reactors that have rows of UV lamps. It is known to offset successive rows so that the fluid passes through the spaces between the lamps in the first row and contacts the lamps in the second row. A patent to Wedekamp, U.S. Pat. No. 5,200,156, (“Wedekamp”) discloses one such system. The primary concern disclosed in Wedekamp was offsetting the lamps so that the light can pass upstream and downstream unobstructed.
However, the system disclosed in Wedekamp and other traditional UV systems have failed to provide a apparatus that is able to equally distribute UV dose throughout the system, and that is therefore capable of achieving uniformity in dose. The failure of those traditional systems relates to a phenomenon that has been, up until now, ignored. That phenomenon is that the UV lamps that are used to treat fluids emit less UV in the downward direction than in the upward direction. This is particularly relevant with large medium pressure mercury arc lamps. Therefore, in traditional systems wherein the UV light sources are arranged next to one another and sometimes in offset rows, there could be areas in the reactor where the dose is low. This is especially so in the area below the lamps, where, as described above, the lamp output is reduced, thereby contributing to a low dose in this zone and hence a wide dose distribution. Therefore, a traditional system may provide some of the fluid with a low dose of UV and some of the fluid with a high dose. Ideally, UV treatment systems and methods would provide a narrow dose distribution.
It would therefore be desirable to eliminate the undesirable effect of a non-uniform dose distribution. It would further be desirable to increase uniformity in dose distribution by causing more of the fluid to flow into the treatment area.
Another problem in designing UV reactors for treatment of fluids is that in an installed system, the fluid quality and flow rate may vary from one system to another and from moment to moment. Thus, there is a need for modular assemblies that can be incorporated into a reactor in any number to account for such variations.